This STTR program will test the utility of a low-cost device for noninvasive liver iron measurements, by using the device to determine the prevalence of iron overload in African Americans. African American iron overload is both an under-studied health issue in a medically underserved population, and an example of the wider problem of mild to moderate iron overload in conditions such as liver disease and metabolic syndrome. In all of these settings, the prevalence, causes and effects of excess iron are poorly understood, in part because existing methods of measuring iron stores are unreliable (serum ferritin), invasive (liver biopsy), or expensive and inconvenient (magnetic resonance imaging). The new device offers a new way to measure iron stores. This room-temperature magnetic susceptometer uses inexpensive technology to detect the magnetic-field response of iron in the liver. It can potentially make liver iron measurements in any hospital clinic, for a fifth of the cost of MRI. Recent tests show that new system is well correlated (r=0.93) with existing susceptometers that use Super- conducting QUantum Interference Devices (SQUIDs), in patients with transfusional iron overload. However, to benefit the largest numbers of patients, the new device needs to measure not only the severely elevated liver iron caused by chronic blood transfusions, but the milder iron elevations characteristic of metabolic syndrome, liver disease and African American iron overload. This program aims to achieve that improved accuracy, and demonstrate the low-cost susceptometer's usefulness as a tool to study iron overload. Phase I has three specific aims: 1. Improve susceptometer's accuracy by more effectively correcting for tissue overlying the liver. 2. Validate accuracy by determining measurement variability in subjects with normal iron stores. 3. Design Phase II study investigating prevalence, effects and causes of African American iron overload. Phase II will (a) further improve measurement accuracy as needed, (b) compare liver iron in normal subjects and patients whose serum ferritin and transferrin saturation indicate increased risk of iron overload, and (c) examine associations of elevated liver iron with health effects including liver damage, cardiomyopathy and diabetes, as well as genetic changes affecting iron metabolism. This project, in collaboration with Victor Gordeuk of Howard University, will put the new iron measurement system in the hands of an established iron-overload research program. It will both improve our understanding of iron overload in African Americans, and show that an inexpensive device can measure the mild to moderate iron overloads found in diseases that affect millions of patients. This broader capability may open up a $300M/year market for noninvasive measurements of iron stores. This project thus advances both medical science and medical device technology. PUBLIC HEALTH RELEVANCE: This program will illuminate the poorly understood health problem of iron overload, or accumulation of excess iron, in African Americans. It will also give clinicians and medical researchers an affordable, accurate, non-invasive way to measure iron overload in many other settings, such as sickle-cell disease, liver disease, metabolic syndrome, blood disorders such as myelodysplastic syndrome, and dialysis for kidney disease. This new diagnostic tool, and the improved medical knowledge that it makes possible, will benefit millions of patients.